270 Win with 140 Accubonds - how far off the lands to start?

[Dr. Vette]

I'm getting ready to work on my second-ever reloading project, my 270 Winchester chambered Wby Vanguard. It's already an accurate rifle with factory ammo, so I'm hoping for great things with handloads. :shock:

The distance to the lands as measured with my RCBS Precision Mic is 0.106. I set up a dummy load at virtually full length and had no problems both in the magazine and cycling it through the action. I now have my seater adjusted to make loads about 0.011 off the lands and attached a photo of that load below (no micrometer seater for this die, so 0.011 it is).

As you can see in the attached photo there is still plenty of bullet in the case at this length, more than a caliber's distance. I also have at the bottom of the photo the factory 130gr Winchester ammo that already shoots great in this rifle, though obviously a very different bullet and length. Searching around I see anywhere from 0.010 to 0.050 off the lands as a good length, with about 0.020 as the most common.

Any thoughts as to where to go for an initial length? I'll be using H-4831SC with Federal GM210M primers, 140gr Accubonds, and all brass was previously fired in this rifle.

 

[CatskillCrawler]

Start by finding out your OAL when the bullet kisses the lands of your rifle. Next determine how long of an OAL your internal magazine will accommodate. If your magazine's max OAL is less than the chamber's max OAL, you're limited to the magazine's OAL. Whatever the case, back off from whatever max OAL you can use by .010" and start from there.

I've found that ABs like a lot of jump in 3 of the 4 rifles I've used them in. Good luck!

edit - my daughter was yapping at me while I read your post... ignore my first paragraph and just start where you're all set up currently. I don't like to get tighter than .010" with a hunting rifle.

 

[hubcap]

My .270 shoots the 140 AB real well at .085 off the lands. My coal is 3.400. For what ever reason my rifle likes Ab,s and BT,s with a pretty good jump. The same rifle likes Pt,s .025 to .040 off the lands. If the AB don,t shoot up close then seat deeper. Good luck Dr.Vette. Getting the 140 AB to shoot well is worth the effort. I shot a whole box before I got there.

 

[barthowes]

Any bullet i load (with the exception of monolithic) I put at 0.010" off the lands and vary the charge weight to see what it likes first. then I adjust the seating depth if i want to try and tighten my best group up.

 

[SJB358]

All the others gave great advice. I start at mag length or .015" off the rifling, then develop whichever powder charge is most accurate. At that point, I will vary seating depth to see what it likes.

I have found the AB's like more jump into the rifling than I would think is normal, but that is my experience only.

On another note, I am working the other way around on one of my rifles. I actually wanna run the bullet at a certain speed, so once I find that charge that shoots decently and nearly the speeds I want, I will vary seating depth to tighten it up. The rifle I am working with allows me to work back and forth pretty liberally in seating depth. Never done it that way before, so I will let you all know how it goes.

 

[velvetant]

Like others have said NAB seem to like a little jump and my loads with them are the same.
Start .015 off the lands and play with powders and charge weights. If that doesn't work I would seat to .075 off the lands and go from there, My .270 with the 130NAB shoots best .100 off the lands

 

[hubcap]

Like others have said NAB seem to like a little jump and my loads with them are the same.
Start .015 off the lands and play with powders and charge weights. If that doesn't work I would seat to .075 off the lands and go from there, My .270 with the 130NAB shoots best .100 off the lands

.100 off the lands works for me too with the 130 AB.

 

[pre6422hornet]

I am in the middle of this as well with my 270.

my go to load for BT's has a COL of 3.350. To the lands is 3.390. I loaded the AB's to 3.350 and accuracy was erradic.

I just finished loading up (3) each at 3.330, 3.335, 3.340, 3.345, 3.350, 3.355, 3.360 and 3.365.

All once fired brass. Just have to get to the range to test

 

[SJB358]

That should be a great range day Pat. Get you back in tune with that rifle.